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51.
Tony Gutierrez David Berry Tingting Yang Sara Mishamandani Luke McKay Andreas Teske Michael D. Aitken 《PloS one》2013,8(6)
Halomonas
species are recognized for producing exopolysaccharides (EPS) exhibiting amphiphilic properties that allow these macromolecules to interface with hydrophobic substrates, such as hydrocarbons. There remains a paucity of knowledge, however, on the potential of
Halomonas
EPS to influence the biodegradation of hydrocarbons. In this study, the well-characterized amphiphilic EPS produced by
Halomonas
species strain TG39 was shown to effectively increase the solubilization of aromatic hydrocarbons and enhance their biodegradation by an indigenous microbial community from oil-contaminated surface waters collected during the active phase of the Deepwater Horizon oil spill. Three
Halomonas
strains were isolated from the Deepwater Horizon site, all of which produced EPS with excellent emulsifying qualities and shared high (97-100%) 16S rRNA sequence identity with strain TG39 and other EPS-producing
Halomonas
strains. Analysis of pyrosequence data from surface water samples collected during the spill revealed several distinct
Halomonas
phylotypes, of which some shared a high sequence identity (≥97%) to strain TG39 and the Gulf spill isolates. Other bacterial groups comprising members with well-characterized EPS-producing qualities, such as
Alteromonas
,
Colwellia
and
Pseudoalteromonas
, were also found enriched in surface waters, suggesting that the total pool of EPS in the Gulf during the spill may have been supplemented by these organisms. Roller bottle incubations with one of the
Halomonas
isolates from the Deepwater Horizon spill site demonstrated its ability to effectively produce oil aggregates and emulsify the oil. The enrichment of EPS-producing bacteria during the spill coupled with their capacity to produce amphiphilic EPS is likely to have contributed to the ultimate removal of the oil and to the formation of oil aggregates, which were a dominant feature observed in contaminated surface waters. 相似文献
52.
53.
Raquel Amaral Karen P. Fawley Yvonne Němcová Tereza Ševčíková Alena Lukešová Marvin W. Fawley Lília M. A. Santos Marek Eliáš 《Journal of phycology》2020,56(3):630-648
The class Eustigmatophyceae includes mostly coccoid, freshwater algae, although some genera are common in terrestrial habitats and two are primarily marine. The formal classification of the class, developed decades ago, does not fit the diversity and phylogeny of the group as presently known and is in urgent need of revision. This study concerns a clade informally known as the Pseudellipsoidion group of the order Eustigmatales, which was initially known to comprise seven strains with oval to ellipsoidal cells, some bearing a stipe. We examined those strains as well as 10 new ones and obtained 18S rDNA and rbcL gene sequences. The results from phylogenetic analyses of the sequence data were integrated with morphological data of vegetative and motile cells. Monophyly of the Pseudellipsoidion group is supported in both 18S rDNA and rbcL trees. The group is formalized as the new family Neomonodaceae comprising, in addition to Pseudellipsoidion, three newly erected genera. By establishing Neomonodus gen. nov. (with type species Neomonodus ovalis comb. nov.), we finally resolve the intricate taxonomic history of a species originally described as Monodus ovalis and later moved to the genera Characiopsis and Pseudocharaciopsis. Characiopsiella gen. nov. (with the type species Characiopsiella minima comb. nov.) and Munda gen. nov. (with the type species Munda aquilonaris) are established to accommodate additional representatives of the polyphyletic genus Characiopsis. A morphological feature common to all examined Neomonodaceae is the absence of a pyrenoid in the chloroplasts, which discriminates them from other morphologically similar yet unrelated eustigmatophytes (including other Characiopsis-like species). 相似文献
54.
Alexander Jason B. Bunce Michael White Nicole Wilkinson Shaun P. Adam Arne A. S. Berry Tina Stat Michael Thomas Luke Newman Stephen J. Dugal Laurence Richards Zoe T. 《Coral reefs (Online)》2020,39(1):159-171
Coral Reefs - Cumulative anthropogenic pressures have triggered a global decline in the health of marine ecosystems, and coral reefs, in particular, are in crisis. With climate and... 相似文献
55.
Elizabeth Murdoch Titcomb Jessie Stevens Anne Sleeman Brandy Nelson Luke Yrastorza Adam M. Schaefer Gregory D. Bossart John S. Reif Marilyn Mazzoil 《Marine Mammal Science》2020,36(3):858-870
A previously undescribed skin abnormality, referred to as “linear skin markings” (LSM), has been identified in free-ranging common bottlenose dolphins (Tursiops truncatus) in the Indian River Lagoon, Florida (IRL). The lesions were identified during photo-identification surveys conducted from 2002 and 2015. LSM presented as distinct, parallel lines running dorso-ventrally on the torso and varied in length and width. The goals of this study were to determine (1) prevalence of the condition in IRL dolphins, (2) age and sex distribution of affected animals, (3) spatial and temporal distribution patterns, (4) duration of the condition, and (5) development of hypotheses regarding the etiology of the condition. Among 1,357 individual dolphins identified during the study period, 96 (7.0%) showed evidence of LSM. Nearly all (98.8%) cases with an established home range occurred in the northern and central regions of the IRL. The majority of cases of known sex were female (85%), of which 100% had given birth to one or more calves. The mean age of animals with LSM when first observed was 7.3 with a range of 1–20 years. The maximum observed duration of LSM was 15 years. Once observed, the condition persisted indefinitely. The etiology of LSM has not been established. 相似文献
56.
Tadeo Ramirez-Parada Domingo Cabrera Zoe Diaz-Martin Luke Browne Jordan Karubian 《Biotropica》2020,52(5):845-856
Many tropical plant species show wide intra-population variation in reproductive timing, resulting in the protracted presence of flowering and fruiting individuals. Various eco-evolutionary drivers have been proposed as ultimate causes for asynchronous phenology, yet little is known about the proximate factors that control reproductive onset among individuals or that influence the proportion of trees producing new inflorescences within a population. We employed a nine-year phenological record from 178 individuals of the hyperdominant, asynchronously flowering canopy palm, Oenocarpus bataua (Arecaceae)¸ to assess whether resource-related variables influence individual- and population-level flowering phenology. Among individuals, access to sunlight increased rates of inflorescence production, while the presence of resource sinks related to current investment in reproduction—developing infructescences—reduced the probability of producing new inflorescences. At the population level, climate anomalies induced by El Niño Southern Oscillation (ENSO) affected the proportion of the population producing inflorescences through time. Moreover, the effects of ENSO anomalies on flowering patterns depended on the prevalence of developing infructescences in the population, with stronger effects in periods of low developing-infructescence frequency. Taken together, these results suggest that resource-related variables can drive phenological differences among individuals and mediate population-level responses to larger-scale variables, such as climate anomalies. Consequently, a greater focus on the role of resource levels as endogenous cues for reproduction might help explain the frequent aseasonal phenological patterns observed among tropical plants, particularly those showing high intra-population asynchrony. 相似文献
57.
58.
59.
Adam F. Odell Luke R. Odell Jon M. Askham Hiba Alogheli Sreenivasan Ponnambalam Monica Hollstein 《The Journal of biological chemistry》2013,288(23):16704-16714
Exposure to herbal remedies containing the carcinogen aristolochic acid (AA) has been widespread in some regions of the world. Rare A→T TP53 mutations were recently discovered in AA-associated urothelial cancers. The near absence of these mutations among all other sequenced human tumors suggests that they could be biologically silent. There are no cell banks with established lines derived from human tumors with which to explore the influence of the novel mutants on p53 function and cellular behavior. To investigate their impact, we generated isogenic mutant clones by integrase-mediated cassette exchange at the p53 locus of platform (null) murine embryonic fibroblasts and kidney epithelial cells. Common tumor mutants (R248W, R273C) were compared with the AA-associated mutants N131Y, R249W, and Q104L. Assays of cell proliferation, migration, growth in soft agar, apoptosis, senescence, and gene expression revealed contrasting outcomes on cellular behavior following introduction of N131Y or Q104L. The N131Y mutant demonstrated a phenotype akin to common tumor mutants, whereas Q104L clone behavior resembled that of cells with wild-type p53. Wild-type p53 responses were restored in double-mutant cells harboring N131Y and N239Y, a second-site rescue mutation, suggesting that pharmaceutical reactivation of p53 function in tumors expressing N131Y could have therapeutic benefit. N131Y is likely to contribute directly to tumor phenotype and is a promising candidate biomarker of AA exposure and disease. Rare mutations thus do not necessarily point to sites where amino acid exchanges are phenotypically neutral. Encounter with mutagenic insults targeting cryptic sites can reveal specific signature hotspots. 相似文献
60.
Paul M. Rindler Scott M. Plafker Luke I. Szweda Michael Kinter 《The Journal of biological chemistry》2013,288(3):1979-1990
Obesity is a predictor of diabetes and cardiovascular disease. One consequence of obesity is dyslipidemia characterized by high blood triglycerides. It has been proposed that oxidative stress, driven by utilization of lipids for energy, contributes to these diseases. The effects of oxidative stress are mitigated by an endogenous antioxidant enzyme network, but little is known about its response to high fat utilization. Our experiments used a multiplexed quantitative proteomics method to measure antioxidant enzyme expression in heart tissue in a mouse model of diet-induced obesity. This experiment showed a rapid and specific up-regulation of catalase protein, with subsequent assays showing increases in activity and mRNA. Catalase, traditionally considered a peroxisomal protein, was found to be present in cardiac mitochondria and significantly increased in content and activity during high fat feeding. These data, coupled with the fact that fatty acid oxidation enhances mitochondrial H2O2 production, suggest that a localized catalase increase is needed to consume excessive mitochondrial H2O2 produced by increased fat metabolism. To determine whether the catalase-specific response is a common feature of physiological conditions that increase blood triglycerides and fatty acid oxidation, we measured changes in antioxidant expression in fasted versus fed mice. Indeed, a similar specific catalase increase was observed in mice fasted for 24 h. Our findings suggest a fundamental metabolic process in which catalase expression is regulated to prevent damage while preserving an H2O2-mediated sensing of diet composition that appropriately adjusts insulin sensitivity in the short term as needed to prioritize lipid metabolism for complete utilization. 相似文献